SpringBoot简单集成WebSocket（纯后端）

1. 引入依赖

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.7</version>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-websocket</artifactId>
</dependency>

2. 编写一个WebSocketConfig

package com.ksxx.test.service;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;

@Configuration
public class WebSocketConfig {

    @Bean
    public ServerEndpointExporter serverEndpointExporter() {
        return new ServerEndpointExporter();
    }
}

3. 编写一个ServerEncoder继承Encoder，这个编译器是为了可以发送对象信息

package com.ksxx.test;

import com.alibaba.fastjson.JSON;
import javax.websocket.Encoder;
import javax.websocket.EndpointConfig;

public class ServerEncoder implements Encoder.Text<Object> {

    @Override
    public void destroy() {
        // TODO Auto-generated method stub
    }

    @Override
    public void init(EndpointConfig arg0) {
        // TODO Auto-generated method stub
    }

    @Override
    public String encode(Object obj) {
        return JSON.toJSONString(obj);
    }
}

4. 编写一个WebSocketBacklogServer (其中type为类型，可多种连接类型)

package com.ksxx.test;

import org.springframework.stereotype.Component;
import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.concurrent.ConcurrentHashMap;

@ServerEndpoint(value="/websocket/{type}/{userId}", encoders = { ServerEncoder.class })
@Component
public class WebSocketBacklogServer {

    //存放每个客户端对应的MyWebSocket对象。
    private static ConcurrentHashMap<String, WebSocketBacklogServer> webSocketSet = new ConcurrentHashMap<String, WebSocketBacklogServer>();

    //与某个客户端的连接会话，需要通过它来给客户端发送数据
    private Session session;

    //接收userId
    private Integer userId;
    //类型    待办:backlog、消息数量:message、即时通讯:chat
    private String type;

    /**
     * 连接建立成功调用的方法*/
    @OnOpen
    public void onOpen(Session session,@PathParam("userId") Integer userId,@PathParam("type") String type) {
        this.session = session;
        webSocketSet.put(type+","+userId,this);     //加入set中
        this.userId=userId;
        this.type=type;
    }

    /**
     * 连接关闭调用的方法
     */
    @OnClose
    public void onClose() {
        System.out.println(userId+type);
        webSocketSet.remove(type+","+userId);  //从set中删除
    }

    /**
     * 收到客户端消息后调用的方法
     *
     * @param message 客户端发送过来的消息*/
    @OnMessage
    public void onMessage(String message, Session session) {
        System.out.println("收到来自窗口"+userId+"的关于"+type+"信息:"+messag);
    }

    /**
     *
     * @param session
     * @param error
     */
    @OnError
    public void onError(Session session, Throwable error) {
        System.out.println("发生错误");
        error.printStackTrace();
    }

    /**
     * 推送
     */
    public void sendMessage(String message) throws IOException {
        this.session.getBasicRemote().sendText(message);
    }
    
    /**
     * 推送
     */
    public void sendMessage(Object message) throws EncodeException,IOException {
        this.session.getBasicRemote().sendObject(message);
    }

    /**
     * 发送消息到所有客户端
     * @param message
     * @throws EncodeException
     * @throws IOException
     */
    public void sendMessageInAll(Object message) throws EncodeException,IOException {
        for(WebSocketBacklogServer value : webSocketSet.values()) {
            value.session.getBasicRemote().sendObject(message);
        }
    }

    /**
     * 指定给某个连接发送信息
     * */
    public static void sendInfo(Object message,Integer userId,String type) throws EncodeException,IOException {
        webSocketSet.get(type+","+userId).sendMessage(message);
    }

}

5. 模拟客户端测试连接
   测试地址: http://www.jsons.cn/websocket/
   
6. 模拟客户端测试发送信息
   
   
7. 服务端主动推送信息（对象类），创建一个Controller写一个测试方法测试调用一下即可

package com.ksxx.test.controller;

import com.ksxx.test.service.WebSocketBacklogServer;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@RequestMapping("test")
public class TestController {

    @RequestMapping("aa")
    public void aa(){
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("age",13);
        try {
            WebSocketBacklogServer.sendInfo(jsonObject,1,"chat");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

本文地址：https://blog.csdn.net/October_zhang/article/details/111886986